/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.    
 */
package org.apache.xmlrpc.parser;

import java.io.ByteArrayInputStream;
import java.io.ObjectInputStream;
import java.util.Map;

import sk.pack.var.QName;

import org.apache.ws.commons.util.NamespaceContextImpl;
import org.apache.xmlrpc.common.TypeFactory;
import org.apache.xmlrpc.common.XmlRpcStreamRequestConfig;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;

/**
 * A SAX parser for an {@link org.apache.xmlrpc.server.XmlRpcServer}'s response.
 */
public class XmlRpcResponseParser extends RecursiveTypeParserImpl {
	private int level;
	private boolean isSuccess;
	private int errorCode;
	private String errorMessage;
	private Throwable errorCause;

	/**
	 * Creates a new instance.
	 * 
	 * @param pConfig
	 *            The response configuration.
	 * @param pTypeFactory
	 *            The type factory for creating instances of {@link TypeParser}.
	 */
	public XmlRpcResponseParser(XmlRpcStreamRequestConfig pConfig,
			TypeFactory pTypeFactory) {
		super(pConfig, new NamespaceContextImpl(), pTypeFactory);
	}

	protected void addResult(Object pResult) throws SAXException {
		if (isSuccess) {
			super.setResult(pResult);
		} else {
			Map map = (Map) pResult;
			Integer faultCode = (Integer) map.get("faultCode");
			if (faultCode == null) {
				throw new SAXParseException("Missing faultCode",
						getDocumentLocator());
			}
			try {
				errorCode = faultCode.intValue();
			} catch (NumberFormatException e) {
				throw new SAXParseException("Invalid faultCode: " + faultCode,
						getDocumentLocator());
			}
			errorMessage = (String) map.get("faultString");
			Object exception = map.get("faultCause");
			if (exception != null) {
				try {
					byte[] bytes = (byte[]) exception;
					ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
					ObjectInputStream ois = new ObjectInputStream(bais);
					errorCause = (Throwable) ois.readObject();
					ois.close();
					bais.close();
				} catch (Throwable t) {
					// Ignore me
				}
			}
		}
	}

	public void startDocument() throws SAXException {
		super.startDocument();
		level = 0;
		isSuccess = false;
		errorCode = 0;
		errorMessage = null;
	}

	public void startElement(String pURI, String pLocalName, String pQName,
			Attributes pAttrs) throws SAXException {
		switch (level++) {
		case 0:
			if (!"".equals(pURI) || !"methodResponse".equals(pLocalName)) {
				throw new SAXParseException(
						"Expected methodResponse element, got "
								+ new QName(pURI, pLocalName),
						getDocumentLocator());
			}
			break;
		case 1:
			if ("".equals(pURI) && "params".equals(pLocalName)) {
				isSuccess = true;
			} else if ("".equals(pURI) && "fault".equals(pLocalName)) {
				isSuccess = false;
			} else {
				throw new SAXParseException(
						"Expected params or fault element, got "
								+ new QName(pURI, pLocalName),
						getDocumentLocator());
			}
			break;
		case 2:
			if (isSuccess) {
				if (!"".equals(pURI) || !"param".equals(pLocalName)) {
					throw new SAXParseException("Expected param element, got "
							+ new QName(pURI, pLocalName), getDocumentLocator());
				}
			} else {
				if ("".equals(pURI) && "value".equals(pLocalName)) {
					startValueTag();
				} else {
					throw new SAXParseException("Expected value element, got "
							+ new QName(pURI, pLocalName), getDocumentLocator());
				}
			}
			break;
		case 3:
			if (isSuccess) {
				if ("".equals(pURI) && "value".equals(pLocalName)) {
					startValueTag();
				} else {
					throw new SAXParseException("Expected value element, got "
							+ new QName(pURI, pLocalName), getDocumentLocator());
				}
			} else {
				super.startElement(pURI, pLocalName, pQName, pAttrs);
			}
			break;
		default:
			super.startElement(pURI, pLocalName, pQName, pAttrs);
			break;
		}
	}

	public void endElement(String pURI, String pLocalName, String pQName)
			throws SAXException {
		switch (--level) {
		case 0:
			if (!"".equals(pURI) || !"methodResponse".equals(pLocalName)) {
				throw new SAXParseException(
						"Expected /methodResponse element, got "
								+ new QName(pURI, pLocalName),
						getDocumentLocator());
			}
			break;
		case 1: {
			String tag;
			if (isSuccess) {
				tag = "params";
			} else {
				tag = "fault";
			}
			if (!"".equals(pURI) || !tag.equals(pLocalName)) {
				throw new SAXParseException("Expected /" + tag
						+ " element, got " + new QName(pURI, pLocalName),
						getDocumentLocator());
			}
			break;
		}
		case 2:
			if (isSuccess) {
				if (!"".equals(pURI) || !"param".equals(pLocalName)) {
					throw new SAXParseException("Expected /param, got "
							+ new QName(pURI, pLocalName), getDocumentLocator());
				}
			} else {
				if ("".equals(pURI) && "value".equals(pLocalName)) {
					endValueTag();
				} else {
					throw new SAXParseException("Expected /value, got "
							+ new QName(pURI, pLocalName), getDocumentLocator());
				}
			}
			break;
		case 3:
			if (isSuccess) {
				if ("".equals(pURI) && "value".equals(pLocalName)) {
					endValueTag();
				} else {
					throw new SAXParseException("Expected /value, got "
							+ new QName(pURI, pLocalName), getDocumentLocator());
				}
			} else {
				super.endElement(pURI, pLocalName, pQName);
			}
			break;
		default:
			super.endElement(pURI, pLocalName, pQName);
			break;
		}
	}

	/**
	 * Returns whether the response returned success. If so, the result object
	 * may be fetched using {@link #getResult()}. Otherwise, you may use the
	 * methods {@link #getErrorCode()} and {@link #getErrorMessage()} to check
	 * for error reasons.
	 * 
	 * @return True, if the response indicated success, false otherwise.
	 */
	public boolean isSuccess() {
		return isSuccess;
	}

	/**
	 * If the response contained a fault, returns the error code.
	 * 
	 * @return The numeric error code.
	 */
	public int getErrorCode() {
		return errorCode;
	}

	/**
	 * If the response contained a fault, returns the error message.
	 * 
	 * @return The error message.
	 */
	public String getErrorMessage() {
		return errorMessage;
	}

	/**
	 * If the response contained a fault, returns the (optional) exception.
	 */
	public Throwable getErrorCause() {
		return errorCause;
	}
}
